Want to make my VZ SS 5.7 go faster

[Crazykent]

Partly depends on cam choice. If you get small cam then you will still feel faster in mid rev range. If you get a big cam then will only notice it right at peak revs.

Where abouts are you located CrazyKent? Mines manual now but could maybe take you for a drive.

Oh ok. That makes sense. In monbulk mate. Thats ok! i appreciate the offer but im just gonna take it down the shop and get it down. Thankyou you've been very helpful also. Great forum this!

[Crazykent]

And here's a pic so u can see what im working with

[D_BLOCK]

My old SSZ was the same colour and I loved it. Those mags look good can you get a better shot of them, I cant tell if its a white of silver inlay into the black.

Jas

[Solone]

I reckon closer to $1500 for those mods. Best value for diff gears IMO is to source a M6 3.46 or Clubby 3.73, if that's what you're after, complete LSD and put it in rather than rebuild the current diff.

I chucked in a set of 3.46 diff gears in my auto.. It adds acceleration but gears are much shorter now

I wouldn't go 3.73 or 3.9 in an auto, way too short, makes car quicker but too short and it drives like a hobo

[dezza]

i put 3.7s in my auto vy clubby and to be honest i wish i went 3.9s
the 3.7s were great with a maffless tune didnt really chew any more fuel was quicker seat of your pants acceleration off the line

[itsme4g63]

If you don't want to bust the engine open:

-OTR
-Long tube headers
-Full exhaust.

Those paired with a diff and dyno tune will make the car reasonably faster over stock.

But, that might not be enough, so:

-243 heads
-228ttr cam

these two will net you the most hp, you will need a better clutch, best bang for buck is the ls7 clutch/flywheel combo.

[whitels1ss]

you will need a better clutch, best bang for buck is the ls7 clutch/flywheel combo.

His car is an Auto buddy

[itsme4g63]

His car is an Auto buddy

Snap, didn't see that at first.

[whitels1ss]

Snap, didn't see that at first.

Hey I have made the same kind of mistake before.....once or more times

[kangavxss]

I chucked in a set of 3.46 diff gears in my auto.. It adds acceleration but gears are much shorter now

I wouldn't go 3.73 or 3.9 in an auto, way too short, makes car quicker but too short and it drives like a hobo

Rubbish. Changed from 3.07 to 3.73 and its the best mod ive done, drives like a dream ( push you back in your seat acceleration off the line and kick down is almost neck snapping) nothing short about them , love it..

[white lie]

I agree, even 4.11's didn't make the gears anywhere near too short. Just revs a little high on the highway/freeway for my liking.

[RARASV8]

sorry for this
now this is a very old post on this forum, it took me 2 hours to find and i knew what i was looking for but here goes.




jeff3205






Re: Suggestions please

Hi VX SS,

I bought a VXII SS M6 about 2 weeks ago. I have spent too much time over the past month on this forum investigating what modifications to do, so I thought I would share the results of my research with you. I haven't done these yet (but am planning to do so in January) so if I am out on any of the details, those who have please feel free to set me straight! All prices are for Melbourne.

Conventional wisdom seems to be that the most cost-effective mods are diff gear ratio, exhaust, cold air intake and LS1 edit.

I am not sure whether you have an A4 or M6. For the M6 which has a 3.46:1 final drive ratio stock, changing to 3.91:1 reportedly gives a substantial increase in performance, aids driveability and improves economy. For the A4 which has 3.07:1 stock, the recommended change is to 3.46:1. I have been pricing 3.91s - supplied and fitted the going rate is around $1,200. If you have an A4 then fitting 3.46s will be cheaper as there are quite a few used 3.46 gearsets around, mostly from M6 drivers who are upgrading. A4 maybe $200 cheaper if you can source used parts this way. I will be selling my used 3.46s in the new year if you are interested.

Note that if you change the diff gear ratio you will need to get the PCM (powertrain control module) updated so that the speedo reads correctly after the change. To get the PCM changed just for this seems to be around $150 if done via tuner with the LS1 edit software. Although if the tuner also does the diff gears then the PCM change might be included in the diff gears price - not sure about that. If you have a tune done with LS1 edit (see below) then the speedo recalibration should be included in the edit tune price.

Other changes: LS1 edit gives a big improvement on its own, or if done with exhaust and intake then it also optimises the effect of those mods. Get the LS1 edit done last.

Exhaust mods are in 3 parts - extractors, catalytic converters (cats) and the exhaust from the cats back (cat-back). Extractors come in Tri-Y shape or 4-into-1 shape. Tri-Y is better for low-rpm torque and is the choice for street driving. 4-1 give better high-rpm power and is the choice if quarter mile times are the goal. Extractors are around the $700 mark. HPC (high performance coating) on the extractors keeps heat in the exhaust and out of the engine bay and costs extra - I haven't priced this yet. Extractors come in different pipe diameters. 1 5/8th inch diameter pipes work well on the street - talk with the shop to confirm suitability for your needs.

With cats, you can have the factory cats opened up (the pipework to/from the cats enlarged) or get new aftermarket hi-flow cats. I have had the factory cat mod priced at $315. New cats are more expensive. Hi-flowing the factory cats seems to be fine.

Re the cat-back, you can go from $600 cheapies with press bends in mild steel up to $1500+ for custom-made mandrel bent systems with stainless steel. The main advantage of stainless is that it lasts longer. Mild steel can rust out in 2 years. A very important consideration is how much drone the exhaust produces. The better shops can build the exhaust so that there is no drone. For street driving the best system appears to be a twin 2.5 inch pipe diameter. Also, the cat back system will include some sort of pipe between the two exhaust pipes. A common type of crossover is called a kiss pipe whereby the two exhaust pipes merge together then diverge after the merge (i.e. the two pipes "kiss"). Apparently this is not ideal as the cross section in the merge section is quite restrictive. It seems that an "X" shape manufactured pipe section gives less restriction than the kiss style pipe.

I have priced a full exhaust including extractors, cat mod and mild steel cat-back at $2,020 from G&D. If I was in Sydney I would go to Sureflow as many people rave about them in the forums. I was actually considering buying a sureflow system and having it sent down for fitting, but will probably just go with a Melbourne supplier in the end for convenience.

Re cold air intakes, the most cost effective way is to install a cold air box from a Monaro. This is then modified so that there is a second hole in the airbox with a tube leading into it. The parts are under $30 if you do the mod yourself. Tuners providing a different cold air setup charge up to $500. Another alternative is an "over the radiator" cold air box, although these are not generally available in a format that allows the MAF to be retained (see below). The OTR setup seems to be superior, but you tend to lose the factory look under the bonnet. Powertorque sells an OTR CAI that looks almost factory (around $600), but you generally need to remove the radiator shroud. I will probably go with the traditional airbox routing as I am not going to keep my car for more than 2 years and want to have it look more or less stock for a prospective purchaser.

Also, the pipe that runs from the airbox to the throttle body (called MAF pipe or TB pipe) should be changed. The most common replacement is the item used on the HSV GTS. This can be used without a MAF (as per GTS) or modified so it fits with the MAF retained. I believe the factory price of the GTS pipe is around $165 (more if sourced from a tuned, and included in the $500 intake system referred to above).

The final mod is to remap the PCM using the LS1 edit software. This enables the PCM to be completely rewritten with substantial gains in performance. There are two schools of thought on this. One is to retain the MAF (mass airflow sensor). The other is to remove the MAF, thereby having the PCM calculate the airflow into the engine based on manifold pressure and rpm. Both seem to work well. Note that the HSV GTS is MAFless from the factory. Some tuners swear that MAFless gives better performance, in part because the MAF is removed thereby reducing restriction in the intake system. Sam's Performance, Dick's and F1 Performance amongst others are proponents of MAFless tuning. G&D is the most prominent proponent of retaining the MAF. For engines under maybe 240rwkw it seems that keeping the MAF is not detrimental to power output. MAFless tuning seems to be around $1,500, whilst tuning with the MAF is around $1,000.

Overall the above mods will likely be around the $5k mark from what I have priced in Melbourne (although I have only gotten a quote from G&D so far). This should give 220+rwkw which is over 300kw at the flywheel - not bad for the cost of a VX + $5k and a hell of a lot cheaper than buying a GTS!

Some other minor mods include altering the thermostat so that the engine runs cooler and allowing more advance to be programmed into the PCM. This allow tuning for a bit more power and costs under $200 from memory in conjunction with other work.

Finally some people are changing the pulley size for the accessory drive belt so that the accessories are driven slower (called an underdrive pulley). This reduces the power used up to drive the accessories, thereby giving more power at the wheels. I have costed this at around $600 and for the gain involved I will not be doing it.

The other mod I will probably do on my M6 is to have a new shifter installed. The Harrop short shifter is around $300 plus installation. The RIPshift from GM motorsport is around $750 fitted. Many forum members are of the view that the RIPshift is superior, including some who had the Harrop and then changed to the RIPshift. Apparently this change transforms the feel of the M6.

Re suppliers in Melbourne, G&D and F1 both have their fans in the forums.

So there you have it - a summary of what I have gleaned from maybe 30 hours of trawling through this forum with the same agenda as you. I hope you have found this helpful.

Regards,
Jeff - South Melbourne


the original thread is here http://www.ls1.com.au/forum/showthre...ff3205-post%29
all still relevant to nearly 9 years later

Garry

[bozodos]

I'd say some of it is a little out of date, like reccommending 'high flowing' stock cats, changing thermostats and fitting the Monaro CAI though.

[Crazykent]

[Crazykent]

Hey thanks RARASV8 thats good information.